Apparatus, systems, and methods for generating force in electromagnetic systems

ABSTRACT

Apparatus, systems, and methods used to produce linear and rotational motion, acceleration, and actuation by the use of mobile ferromagnetic or permanent magnets subjected to asymmetric electromagnetic field distributions are disclosed herein. A variety of exemplary embodiments and applications are described, involving different coil and actuator geometries to include and allow for both stationary and moving magnets, electric fields, and magnetic fields.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 63/086,737, filed on Oct. 2, 2020, which is incorporatedherein by reference in its entirety.

FIELD

The present disclosure is generally directed to electromagneticmachines, and more specifically to electromagnetic actuators.

BACKGROUND

In a general electromagnetic force-generating system, a current-carryingconductor, which by Oersted's Law generates a magnetic field (given byBiot-Savart), interacts with an external magnetic field, and thus, aforce on both the conductor and a source of the external magnetic fieldis generated. According to well established laws of electrodynamics,this interaction, when asymmetric, produces motion.

For example, in a common solenoid device (such as the solenoid deviceillustrated in and discussed below with reference to FIGS. 1A and 1B), arigid magnetic or ferromagnetic (non-permanent) object, commonly termeda plunger or a core (or sometimes, an armature, not to be confused withthe use of armature in electrical technology, meaning a framework ofcoil windings), is suspended near or partly within a cylindricalcurrent-carrying solenoid (which may also be referred to as a coil). Theapplication of current in the coil generates a magnetic force thatpropels the object along the axis of the coil, always in such a manneras to pull the plunger toward the midpoint of the coil. In this example,the force that is experienced by the plunger is dependent on theposition of the plunger along the axis of the solenoid magnetic field.The maximum force on the plunger occurs when one end of the plunger isat the endpoint of the coil (FIG. 1A). The equilibrium point of zero netforce occurs when the midpoint of the plunger aligns with the midpointof the coil (FIG. 1B). This is because, when at the midpoint of thecoil, equal and opposite magnetic forces act on the N and S ends of theplunger concurrently. When a non-magnetic extension of the plunger isused to cause an action to take place outside the end of solenoid, thesystem is commonly referred to as a proportional, axial, or linearactuator. The range of motion, with a maximum range of motion beingone-half the length of the plunger, defines a stroke of the solenoidlinear actuator.

In existing solenoid linear actuators, the net magnetic force that actson the object (plunger) in motion, typically a ferromagnetic rod or apermanent magnet, is generally linear along the entire stroke except atthe opposing ends of the coil. Thus, as noted above, the maximum strokeis limited to half the coil length. However, linear forces are notalways ideal in linear actuator applications. Thus, there is acontinuing need for improved linear actuators, including thoseconfigured to provide nonlinear forces, and especially those configuredfor a longer stroke for the same coil length.

SUMMARY

Disclosed herein are apparatus and methods for generating nonlinearforce in electromagnetic actuator systems. The apparatus and methodsdisclosed herein are configured with one or more coils arranged toprovide a nonuniform (asymmetric) field distribution, yielding a longerstroke than previously achievable with known solenoid linear actuators.In some embodiments, the disclosed apparatus and methods are directed tolinear actuators. In some of those embodiments, the linear actuators areconfigured to provide nonlinear acceleration.

Such linear actuators (as those described herein) can be used in variousapplications. For example, the disclosed technology can be used forhigh-performance, long-stroke linear, and/or rotational actuators. Thedisclosed linear actuators can also be used, for example, when anapplication involves either crushing or stretching a target. Often, theforces on the object may be better suited if they are not linear inthese cases, as the force required to crush or stretch an object changesover the length of the stroke (i.e., the required force is nonlinear).As yet another example, it may be advantageous to have nonlinearacceleration in situations where the smooth transition of speed of theobject in motion is desired, such as in accelerating a passenger trainor a car.

As a general overview of the disclosed linear actuators, a ferromagneticobject, after being inserted axially into a current-carrying coil, willexperience a force, which projects the ferromagnetic object toward thecenter of the coil where the forces on the moving ferromagnetic objectfrom each of the poles find equilibrium. It will be appreciated thatshorter coils possess a shorter distance to the midpoint than do largercoils, so the stroke is shorter in a shorter coil relative to a largercoil. To increase the stroke without increasing the length of a coil, weadd a slightly shorter secondary winding on the outside and towards oneend of a primary coil (as illustrated in and discussed below withreference to FIG. 2A). Now a ferromagnetic object can be moved to aslightly displaced position from the center of the coil as the object isbrought to equilibrium within the two coils acting on it. Theferromagnetic object therefore can be displaced past the center of thecoil, toward the end with the secondary winding. As shorter and shortercoils of increasing radius are added to the periphery of a solenoid, anddisplaced or offset toward one end thereof, the equilibrium point can bedisplaced further towards one pole of the innermost solenoid coil (asillustrated in and discussed below with reference to FIG. 2B). There maybe a limit to how close the equilibrium and/or the ferromagnetic objectcan move or shift toward one pole. The objective, however, can be thatan object using this system attains the advantage of a much longer rangeof actuation as compared to known solenoid coil winding geometry.

One exemplary objective of the linear actuators disclosed herein is togenerate a longer stroke than previously achievable with a single-coilsolenoid actuator of the same length. In effect, the asymmetriclayered-coil geometry can create a non-linear magnetic field densityalong the solenoid, which preponderates towards one end thereof, thusenabling a wider range of motion. Using this kind of system, it may bepossible for a magnetic object in motion in a linear actuator toexperience a force that propels the magnetic object along the nearlyentire length of the coil before it reaches the point at which opposingforces begin to bring the magnetic object to rest (equilibrium). Usingmultiple coils with differing levels of current such that the forcepreponderates from one coil to the next can be an alternative way ofachieving this effect (as illustrated in and discussed below withreference to FIGS. 3A and 3B). Whichever embodiment the invention takes,so long as the magnetic field distribution is nonuniform, the length ofthe stroke can be increased over that of a comparable coil possessing auniform magnetic field distribution. It is advantageous for there to bemechanical stops in the actuator to stop the plunger from going past thelimits of the plunger's stroke, so as to always be able to reverse thepolarity supplied to the solenoid, thereby reversing the direction offorces on a plunger, which may have been, for example, a permanentmagnet that is magnetized throughout its length.

These and other features, aspects, and/or advantages of the presentdisclosure will become better understood with reference to the followingdetailed description and the claims. The accompanying drawings, whichare incorporated in and constitute a part of this specification,illustrate embodiments of the disclosed technology and, together withthe description, explain the principles of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are schematic diagrams of a known solenoid with a singlecoil and a ferromagnetic plunger in a maximum-force configuration and azero net force configuration.

FIGS. 2A and 2B are schematic diagrams of one exemplary embodiment of alinear actuator including a solenoid with a plurality of layered coilsdisplaced toward one end of a primary coil, in accordance with thepresent disclosure.

FIGS. 3A and 3B are schematic diagrams of another exemplary embodimentof a linear actuator including a plurality of separate coils arranged ina linear configuration, in accordance with the present disclosure.

FIGS. 4A and 4B are schematic diagrams of another exemplary embodimentof a linear actuator, wherein the use of nonuniform electric fieldsgenerates asymmetric electromagnetic forces that tend to attract theactuating plunger towards the point of highest electric potential, inaccordance with the present disclosure.

FIGS. 5A-5C are schematic diagrams of another exemplary embodiment of alinear actuator, wherein the field distribution gradient takes placealong a curved route, so as to create a rotational actuator, inaccordance with the present disclosure.

FIG. 6 is a schematic diagram of another exemplary embodiment of alinear actuator, wherein a plurality of separate coils with differingturn counts are used to create the asymmetrical magnetic flux density,in accordance with the present disclosure.

FIGS. 7A and 7B are schematic diagrams of another exemplary embodimentof a linear actuator, wherein concatenated permanent magnets ofincreasing field strength are utilized to produce an asymmetrical fluxdensity, and a coil configured to, with electric current appliedthereto, produce motion of either the permanent magnets or the coilitself, in accordance with the present disclosure.

FIGS. 8A and 8B are schematic diagrams of another exemplary embodimentof a linear actuator, wherein two sets of coil geometries are arrangedon opposite ends of the actuator axis, each set connected to a separatea voltage source and potentiometer, which is configured to create apush-pull effect, and a maximally variable axial profile of the magneticflux density, in accordance with the present disclosure.

FIG. 9 is a schematic diagram of an exemplary plunger configured for usethe exemplary actuator of FIGS. 8A and 8B.

FIG. 10 is a schematic diagram of an exemplary coil core that can beutilized in combination with the exemplary actuators disclosed herein.

FIG. 11 is a schematic diagram of another exemplary embodiment of alinear actuator, in accordance with the present disclosure.

FIG. 12 is an exemplary curve illustrating distance by the inversesquare function for the actuators disclosed herein.

FIG. 13 is a schematic diagram of showing acceleration of ionizedparticles over a wider length due to a nonhomogeneous electric field, inaccordance with the present disclosure.

FIG. 14 is a logical block diagram of an exemplary actuator andcontroller system, in accordance with the present disclosure.

DETAILED DESCRIPTION General Considerations

The systems and methods described herein, and individual componentsthereof, should not be construed as being limited to the particular usesor systems described herein in any way. Instead, this disclosure isdirected toward all novel and non-obvious features and aspects of thevarious disclosed embodiments, alone and in various combinations andsubcombinations with one another. For example, any features or aspectsof the disclosed embodiments can be used in various combinations andsubcombinations with one another, as will be recognized by an ordinarilyskilled artisan in the relevant field(s) in view of the informationdisclosed herein. In addition, the disclosed systems, methods, andcomponents thereof are not limited to any specific aspect or feature orcombinations thereof, nor do the disclosed things and methods requirethat any one or more specific advantages be present or problems besolved.

As used in this application, the singular forms “a,” “an,” and “the”include the plural forms unless the context clearly dictates otherwise.Additionally, the term “includes” means “comprises.” Further, the terms“coupled” or “secured” encompass mechanical and chemical couplings, aswell as other practical ways of coupling or linking items together, anddo not exclude the presence of intermediate elements between the coupleditems unless otherwise indicated, such as by referring to elements, orsurfaces thereof, being “directly” coupled or secured. Furthermore, asused herein, the term “and/or” means any one item or combination ofitems in the phrase.

As used herein, the term “exemplary” means serving as a non-limitingexample, instance, or illustration. As used herein, the terms “e.g.,”and “for example,” introduce a list of one or more non-limitingembodiments, examples, instances, and/or illustrations.

As used herein, the terms “non-linear” and “nonhomogeneous” aregenerally used to describe the irregular shape of the electric ormagnetic flux lines when they are produced in a way that varies inintensity from one end of the source of the field to the other.

Although the operations of some of the disclosed methods are describedin a particular, sequential order for convenient presentation, thismanner of description encompasses rearrangement, unless a particularordering is required by specific language set forth below. For example,operations described sequentially may in some cases be rearranged orperformed concurrently. Moreover, for the sake of simplicity, theattached figures may not depict the various ways in which the disclosedthings and methods can be used in conjunction with other things andmethods. Additionally, the description sometimes uses terms like“provide” and “produce” to describe the disclosed methods. These termsare high-level descriptions of the actual operations that are performed.The actual operations that correspond to these terms will vary dependingon the particular implementation and are readily discernible by one ofordinary skill in the art having the benefit of this disclosure.

As used herein, the terms “attached” and “coupled” generally meanphysically connected or linked, which includes items that are directlyattached/coupled and items that are attached/coupled with intermediateelements between the attached/coupled items, unless specifically statedto the contrary.

As used herein, the terms “solenoid coil”, “solenoid, and “coil”generally refer to the coil winding part of the linear actuator. Theterm “solenoid actuator” generally refers to the entire actuator as awhole and can distinguish from other forms of linear actuators such ashydraulic, motorized, and pneumatic actuators.

As used herein, the terms “fixedly attached” and “fixedly coupled” referto two components joined in a manner such that the components may not bereadily separated from one another without destroying and/or damagingone or both components. Exemplary modalities of fixed attachment mayinclude joining with permanent adhesive, stitches, welding or otherthermal bonding, and/or other joining techniques. In addition, twocomponents may be “fixedly attached” or “fixedly coupled” by virtue ofbeing integrally formed, for example, in a molding process. In contrast,the terms “removably attached” or “removably coupled” refer to twocomponents joined in a manner such that the components can be readilyseparated from one another to return to their separate, discrete formswithout destroying and/or damaging either component. Exemplarymodalities of temporary attachment may include mating-type connections,releasable fasteners, removable stitches, and/or other temporary joiningtechniques.

Unless explained otherwise, all technical and scientific terms usedherein have the same meaning as commonly understood to one of ordinaryskill in the art to which this disclosure belongs. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present disclosure, suitable methods andmaterials are described below. The materials, methods, and examples areillustrative only and not intended to be limiting. Other features of thedisclosure are apparent from the detailed description, abstract, anddrawings.

Exemplary Embodiments

For reference, FIGS. 1A and 1B depict an example of a known solenoid orlinear actuator 100. As illustrated therein, the linear actuator 100includes a coil 101 and a plunger 108, which is a magnet or a magnetizedobject magnetized through its length with the North Pole 109 of theplunger 108 aiming away from the North Pole 106 of the solenoid. In thisposition, the plunger 108 experiences a net force 112, which can pullthe plunger 108 into the coil 101 due to the magnetic force 105generated by the current source 103. The direction of the current flow104 through a circuit 102 and through the windings of the coil 101determine the polarity of the coil (i.e., the orientation of the NorthPole 106 and the South Pole 107). In this case, the plunger 108 isresting within the first turn 111 of the windings of the coil 101. Awinding 104 a overlaps with another part of the coil in order toillustrate the winding direction of the coil 101. The switch 116 isdepicted in the open position 116 a to show that there is no currentflow through the coil. The mid-point 110 of the plunger 108 is in aposition that allows for a force 112 to be exerted upon the plunger whencurrent is flowing.

As discussed above, the shutting of the switch 117 allows for the flowof current to enter the coil 101 which generates a magnetic force thatpropels the plunger 108 along the axis of the coil, such that theplunger is pulled toward the midpoint of the coil 108. In this example,the force 112 that is experienced by the plunger 108 is dependent on theposition of the plunger along the axis of the solenoid's magnetic field.The maximum force on the plunger 108 occurs when one end of the plungeris at the endpoint of the coil 101 (as illustrated in FIG. 1A). Theequilibrium point of zero net force occurs when the midpoint 110 of theplunger 108 aligns with the midpoint of the coil 101 (as illustrated inFIG. 1B). This is because, when at the midpoint of the coil 101, equaland opposite magnetic forces act on the N and S ends of the plunger 108concurrently. A distance 115 corresponds to the stroke of the solenoidactuator which ends at the center of the coil 113, and is defined by anoriginal position 110 a the center 110 of the plunger 108 and a finalposition 113 of the center 110 of the plunger 108. When the plunger isat position 113, the force on the plunger 114 may be very nearly equalto zero.

One exemplary embodiment of a solenoid linear actuator 200 according thepresent disclosure is shown in FIGS. 2A and 2B. As can be seen therein,the solenoid actuator 200 includes a plurality of coils, which havetheir windings arranged with a geometry that can cause the magneticforce to preponderate towards one pole, and can be configured to actupon a plunger (i.e., magnetized object) 208 along a straight/linearaxis of movement. In the present embodiment, the coil geometry includesmore windings or coils (coils 201, 202, 203) towards one end of thesolenoid actuator 200 relative to the opposing end thereof. It will beunderstood that the plunger or magnetized object 208 can be a temporaryor permanent magnet, a ferromagnetic material, or anotherelectromagnetic coil connected to a source of electricity. It willadditionally be understood that the plunger 208 may be positioned on topof the coils, within the coils, or a combination thereof so long as itcan be acted upon by the nonlinear magnetic field density to produce alonger stroke of actuation relative to the conventional linear actuator100 of FIGS. 1A and 1B, where the peak magnetic field density is locatedin the center of the coil 101 (i.e., at the center of the coil'sbounds).

In some embodiments, an elastic band or spring secured to the magnetizedobject 208 may also be used to create an additional source of force onthe plunger 208 in instances or conditions where it is deemedadvantageous, such as, for example, in instances in which more linearforces across the stroke are desired. In another example, an additionalsource of force or tension can allow for the plunger 208 to return to astarting position after it is moved the full stroke of motion if thepower is subsequently turned off. This can be advantageous if, forexample, an application requires or implements a linear actuator that isdesigned to be connected to a DC source with no option of reversing thepolarity, as this can allow for the plunger in the system to undergoforward movements (due to the magnetic field when the power is turnedoff) and backward movements (due to the tension acting in the opposingdirection when the power is turned off). Furthermore, such embodimentscan be advantageous when a variable power source is used in order toovercome the tension partially but not completely, thereby enablingcontrol or alteration the plunger's position along the solenoid coil.

Returning to FIG. 2A, the plunger 208 in the solenoid actuator 100possesses an asymmetrical magnetic flux density (illustrated by atapering B-field 207). In this case, the plunger 208 is oriented suchthat the north pole 209 thereof is facing the opposite direction of thecoil (i.e., facing away from the coil). The windings of the coil 201span from one end (a first end) of the linear actuator 100 to theopposing (second) end of the actuator. At the opposing end, the coil 201can be connected to where it connects to windings of a second coil 202via a first connecting wire 201 a. The second coil 202 then connects towindings of a third coil 203 via a second connecting wire 202 a. Thewindings of the second coil 202 can be wrapped over a portion of thewindings of the first coil 201 so as to produce a magnetic field densitythat preponderates towards one end (e.g., the right side) of thesolenoid actuator 200. The third coil 203 is wrapped over a portion ofthe windings of the second coil 202 so as to produce a magnetic fielddensity that further preponderates toward one end (e.g., the right side)of the solenoid actuator 200. FIG. 2A specifically illustrates a momentwhen a switch 219 on an electrical circuit is moving from an openposition 216 towards closing, causing current 204 to flow into thesolenoid actuator 200 in a specified direction 205. A winding 203 aoverlaps with another part of the coil in order to illustrate thewinding direction of the coil 201.

FIG. 2B illustrates the solenoid actuator 200 after the switch 219 hasbeen moved into a closed position 217. When the switch 219 is in theclosed position 217, the plunger 208 moved a stroke of distance 215,which is greater that a stroke distance 115 of the solenoid actuator 100depicted in FIG. 1B, when the coils 101 and 201 are of equal or similarlength. This stroke distance 215 depicted in FIG. 2B illustrates thatthe midpoint of the plunger 208 moves from an initial position 210 a) toa resting position 210, which corresponds closely with the peak magneticflux density along the coils 201, 202, 203 of the solenoid actuator 200.The potential B field 207 may be generated or manifested when the switch207 is closed.

When the plunger 208 is held stationary, the coils 201, 202, 203 canexperience a force in the solenoid actuator 200 system. When thepolarity of one or more of the coils 201, 202, 203 is reversed, theforces created by the action of the reversed coil on the othercomponents in the solenoid actuator can be reversed. The number of thewindings in each respective coil 201, 202, 203 and the power flow toeach coil 201, 202, 203 may determine the position of the plunger 208 inthe solenoid actuator 200. Therefore, the present embodiment can enablevariable or adjustable position control of the plunger 208 utilizinge.g., a controller apparatus (such as, the computerized controllerapparatus 1410 discussed below with reference to FIG. 14), especiallywhen the coils are powered separately rather than being joined togetherin one circuit (as in the embodiment of FIG. 6, discussed below). Thegenerated B field 207 a produced by the closing of the switch 216 b isshown in FIG. 2B.

The construction of coils such as those shown in FIG. 2A and FIG. 2B canbe accomplished by altering the graduation in the number of windings ofthe coil. A graduation of one layer of windings may have at least threefewer (−3) windings than the preceding layer. In other words, thewinding count of each consecutive layer can have at least three fewerturns than the previous layer. Each consecutive layer can be displacedtowards one end so that the profile of the coil is similar to that shownin FIG. 2A and FIG. 2B, which is to say that the profile of the solenoidshows that the most windings are conglomerated at or distributed towardone end of the solenoid and there are relatively less on the other end.In alternate embodiments, the coils or windings can be with separatespools of wire, each with different turn counts where the higher numberof turn counts preponderates toward one end, and which are electricallyconnected to the next spool of wire in such a way that the profile ofthe windings takes a form similar to that shown in FIG. 2A and FIG. 2B.The spools of wire may be spaced with minimum distance between them (forexample, 1 mm spacing between the spools of wire). As described above,there may be a minimum difference of three turns of windings betweeneach adjacent spool of wire.

It will be appreciated the applying asymmetrical flux density to alinear actuator can enable prediction or control of the plunger'sstopping point based on the number of windings in the coils and/or thepower flow through their respective circuits. For example, the force onthe plunger along the stroke of the solenoid actuator and/or thestopping position of the plunger can be calculated using mathematicalanalysis allowing further predictability and refinement as one or moreparameters in the system (such as, e.g., power flow) are altered.Furthermore, the apparatus and methods disclosed herein for supplyingpower to a solenoid actuator with variable position control (viacontrolling differences in the power of the branches of the circuit andthe polarity of the coils acting on the plunger) allow for or enable anoperator or a control board to perform actions that previously(utilizing convention solenoid actuators) would have required rathercomplicated controllers including, for example, hydraulic, pneumatic,and/or 3 phase linear motors. Further, conventions solenoid actuatorsare normally only able to perform a single action (e.g., movement of theplunger in a first direction), and all subsequent actions (e.g.,movement of the plunger in an opposing second direction) may require areturn spring or other mechanisms to return the plunger to the point ofhighest force production. The present embodiment depicts oneconfiguration or strategy that can enable full electrical control of theposition of the plunger by incorporating an asymmetrical magnetic fielddensity (such as e.g., the tapering B-field 207 shown in FIG. 2A) alongthe stroke of the plunger.

In some embodiments, an actuator can include a plurality of overlappingcoils that may be turned on or off at will. As such, the coils canintroduce forces to the system in a nonlinear way, thereby allowing agiven apparatus utilizing the actuator to produce multiple forceprofiles, each of which may tend to center an object or plunger inmotion in selected locations and may give rise to different forcesacting on the object or plunger. Where a plurality coils are present andactuated individually, various profiles for forces may be available, asdepicted in FIG. 6 and discussed below.

FIG. 6 illustrates another embodiment wherein a solenoid actuator 600 iscomprised of coils of differing turn count and diameter in order to aidin the production of the magnetic field asymmetry, which can therebylengthen the stroke of plunger. Different from the solenoid actuator600, each of the coils 601 a, 602 a, 603 a in this embodiment isrespectively connected to separate power sources on separate circuits601, 602, 603, which each have a separate power switch 610, 611, 612.The innermost coil 601 a stretches the full length of the solenoidactuator 600 and, when turned on in isolation, the coil 601 a can drawthe plunger 608 to the center point of the coil 601 a. A shorter secondcoil 602 a can be wound over the top of a portion or a section of thefirst coil 601 a so that it is displaced or positioned towards one sideor end (e.g., a right side) of the actuator 600. A third coil 603 a iswound over the second coil 602 a and is similarly displaced orpositioned toward one side or end (e.g., a right side) of the actuator.When Currents I₁, I₂, I₃ can be respectively applied to each of thecoils 601 a, 602 a, 603 a. When the currents I₁, I₂, I₃ are equal andeach circuit has power flowing through the coils 601 a, 602 a, 603 a, amagnetic field is generated in a manner that can cause the peak magneticfield density to be displaced from the center of e.g., the coil 601 atoward one end of the solenoid actuator, and therefore the plunger 608can be moved to a position that is closer toward the end of the solenoidactuator relative to a conventional solenoid actuator (such as e.g., thesolenoid actuator 100 shown in FIG. 1). Further, if the polarity throughone or more of the power sources 601, 602, 603 is reversed, the plunger608 can come to equilibrium at the opposite end of the solenoid actuator600.

In additional or alternate embodiments, a solenoid actuator or a linearmotor configured to generate a nonuniform magnetic field gradient caninclude a plurality of co-linear coils fed by different circuits (suchas in the embodiment of FIG. 6), wherein a positional sensor can allowfor the circuits to switch off as the object passes them so as to reducea force pulling a plunger in motion backward. Further, the circuits canbe controlled (utilizing e.g., a controller apparatus such as, thecomputerized controller apparatus 1410 discussed below with reference toFIG. 14) to change their polarity in order to resist a backward movementof the plunger under circumstances where it is desirable to do so as,for example, when a weighted object is connected to the plunger and itsposition is meant to be held constant. In implementations, the coilsthat are changed to an alternate polarity can be those that are notimmediately neighboring the coils that are still acting on the plungeras to limit destructive interference in their respective magneticfields.

In another exemplary embodiment, a solenoid actuator 300 is shown inFIGS. 3A and 3B. As illustrated therein, the solenoid actuator 300includes a plurality of coils 301, 302, 303 that are linearly arranged,end-to-end, along a common central axis 309 with a gap disposed betweeneach of the coils. In other words, the solenoid actuator 300 includesmultiple non-overlapping coils (the coils 301, 302, 303) arranged alonga common axis. In some examples, the coils 301, 302, 303 are in closeproximity to each other, for example, being separated by a distance of 1mm along the linear axis. In some examples, each of the coils 301, 302,303 can have differing turn counts in the coil and/or differingdiameters of the coil, however, in other examples, the coils can have asimilar or identical number of turns and/or similar or identicaldiameters.

As shown in FIGS. 3A and 3B, the coils 301, 302, 303 can each beconnected to separate circuits 304, 305, 306 (respectively) such thatthe current for each coil can be individually controlled and currentsI₁, I₂, I₃ may selectively differ between the coils. Flux densitiesalong the common axis 309 can therefore be made discontinuous (i.e.,variable) along the axis with a prepondering magnetic flux densitybiased in order to create the desired direction of movement for aplunger 308 (i.e., biased toward a first end or a second apposing end ofthe solenoid actuator 300. Due to the close proximity of the coils 301,302, 303, the magnetic field spans the common axis and the coils 301,302, 303 can act as a single electromagnet, for example, in a similarmanner to the way multiple smaller permanent magnets can be stacked tocreate a field similar to that of a larger permanent magnet. The powerflow to each coil 301, 302, 303 may be altered through the applicationof pulse width modulation. In FIG. 3A, the switches are in the openposition 311 a, 311 b, 311 c, and therefore the potential B field 309 isnot yet active.

Using the solenoid actuator 300, the coils 301, 302, 303 arranged alongthe common axis can be selectively switched on and off in a manner thatmaintains a force on the plunger 308 in motion by generating, forexample, a relatively weak magnetic field at the same position as theplunger and a comparatively stronger magnetic field in front of theplunger as it moves along the axis 309. Additionally or alternatively,in some examples, the magnetic field can be generated such that arepulsive force acts on the moving plunger 308 from behind in order toprovide additional accelerative force on the plunger. This may also beeffective in reducing the tendency of the plunger when accelerating toslip out of the spot or become misaligned when the plunger isexperiencing a maximum accelerative force. Further, a sensor configuredto detect a position of the plunger along the axis can be-utilized forproper timing of switching the circuits 304, 305, 306 for the coils 301,302, 303. By controlling the power flow to each individual coil, it ispossible to create a condition of position control along the axis wherethe plunger is acted on most strongly by the coil with more windingsand/or more power relative to others of the coils. In other words, byselectively turning individual ones of the coils 301, 302, 303 on andoff, only those coils with active power flow act on the plunger 308,which allows fine tuning of position control utilizing e.g., acontroller apparatus (such as, the computerized controller apparatus1410 discussed below with reference to FIG. 14). It will be appreciatedthat the coils 301, 302, 303 can act on the plunger 308 while it isdisposed within the windings and aligned with the common axis 309 (asdepicted in FIGS. 3A and 3B) or the solenoid actuator 300 can functionsimilarly with a plunger that is moving outside of the coils (e.g.,along the top of the coil), as long as the plunger (object) ismagnetized or capable of being magnetized.

FIG. 3A specifically depicts an embodiment where the plunger 308 isbeing acted upon by the coils 301, 302, 303 (which are each on aseparate circuit) at a moment in which switches 312, 313, 314 on each ofthe circuits is moving from an open position 311 towards a closedposition. The current 307 flows through respective circuits 304, 305,306 therefore flows through the coils 301, 302, 303. The three coils301, 302, 303 are separated by a gap 309, and each of can have adiffering current levels (for example, such that the current I₁ flowingin the circuit 306 is greater than the current I₂ flowing in the circuit305, which is greater than the current I₃ flowing in the circuit 304).These differing current levels can generate the asymmetrical fluxdensity 316, which thereby lengthens the stroke of the solenoid actuator300 relative to convention solenoid actuators, such as the solenoidactuator 100.

FIG. 3B illustrates the solenoid actuator 300 after the switches 312,313, 314 on the respective circuits 304, 305, 306 are moved into aclosed position 312. A position 310 a corresponds to a location of themidpoint of the plunger before closing of the switches, while a position310 corresponds to a location of the midpoint of the plunger 308 afterclosing of the switches, which define the stroke distance 315. As notedabove, the stroke distance 315 is greater than that of a conventionalsolenoid linear actuator (such as the solenoid actuator 100) by means ofthe asymmetrical magnetic flux density, which preponderates towards,e.g., the right side of the solenoid actuator 300. A winding 307 aoverlaps with a part of the coil to illustrate a winding direction ofthe coil 301. The switches are shown in the closed position 312 a, 312b, 312 c in FIG. 3B, and therefore the active B field 309 is generatedand capable of acting on the plunger 308.

It will be understood that three coils and circuits are illustrated inthe embodiment of FIGS. 3A and 3B, but in alternate embodiments thesolenoid actuator can include more or fewer coils and circuits (such as,two or four or more coils and circuits). Additionally, in embodiments,the circuits may be connected to a circuit controller, for example, oranother mechanism for generating different field gradients betweenrespective circuits and therefore differing or creating a gradient inthe flux density of the B-field.

In embodiments, the solenoid actuators including multiple coils andcircuits (such as in the embodiments of FIGS. 6A and 6B), as well as theassociated methods for introducing nonuniform magnetic fields may bemade more efficient if the coils, which are behind the plunger, areturned off as the plunger moves past them. In such embodiments, anon-uniform magnetic field can be generated ahead of the plunger via thecoils ahead of the plunger, however the fields that the plunger hasalready moved through are no longer active, so as to yield an evengreater stroke of movement for a given coil or set of coils. Wheremultiple coils are used and switched on and off along a single axis, thecoils may actively reduce the power flow as the moving plunger into thefield of a given coil. In this way, power levels in each consecutivecircuit do not need to continuously increase as the plunger moves alongthe axis. Rather, the movement of the plunger can continue as long asthe power levels of the coil just ahead of the plunger maintains ahigher flux than the coil just behind the moving plunger, therebymaintaining a positive flux gradient in the direction of travel. Inimplementations, the nonuniform field may be oriented in such a way thatthe axis along which the actuation takes place is in a screw-like formaround a cylindrical object. This implementation may allow for moretorque to be developed along the central the axis of the cylinder at theexpense of actuation length.

In embodiments, for breaking or slowing of the plunger, individual onesof the coils that are located behind the moving plunger can turn on asthe plunger moves past them, thereby attracting the plunger in theopposite direction of its momentum and causing the plunger to decelerateor stop its movement. Thus, embodiments disclosed herein can includeelements or employ strategies and methods for resistance to motion alongthe axis of travel of a solenoid actuator configured to generate anon-uniform magnetic field distribution that preponderates toward oneend of the actuator. Further, the embodiments disclosed herein can allowfor a method of producing movements that act against the resistance fora given power input or time period of power input, which can beadvantageous when small or specific changes in the location of theplunger are desired. For example, when the source of resistance is asource of tension or compression between the plunger and a stationaryobject in the system, which may be fixedly attached, the moving plungercan have a displacement that is relative to the power input or theduration of power input. Further, the plunger can return to a positionthat minimizes the tension or compression through ordinary elastic meanswhen power to the coils and circuits is turned off. In another example,a load possessing mass or object, against which it would take power tomove, may be attached to the plunger. Overcoming the resistive losses ofmoving the plunger can then take the place of purposefully employedmechanical or elastic resistance (as in the prior example), as theplunger having the mass attached thereto can inherently create its owninertial and mechanical resistance to motion. Diagrammatically this maytake the same form as in the embodiments of FIGS. 2A and 2B.

In embodiments, two or more coils in a solenoid actuator (or a linearmotor) possessing a non-uniform magnetic field may act to accelerate theplunger in the above examples in opposite directions (by having e.g.,opposite polarity of the input power and/or oppositely wound coildirections) so that small changes in the level of power input or timeinterval of power input to one or more of the coils can causecorresponding changes in the position of the plunger of the actuator ormotor. An example of this is illustrated in the embodiments of FIGS. 8Aand 8B.

In embodiments, the exemplary solenoid actuators disclosed herein mayhave any of a moving coil system, a moving magnet system, or acombination thereof within a non-uniform magnetic field distributionthat preponderates toward one end actuator. For example, a coil may beof ordinary field distribution or it may be designed to produce anon-uniform magnetic field as it acts on a permanent magnet source in aplunger, which itself produces a non-uniform magnetic field as, forexample, the permanent magnet does in the embodiments of FIGS. 7A and7B. Alternatively, two of such permanent magnets or electromagneticcoils may act on the plunger in the system in a manner that the forceswhich they produce on the plunger may be opposite (i.e., in a push pulltopology, similar to that which may occur in the embodiment of FIG. 8)or the forces may be additive (i.e., acting in the same direction). Whenone component is held stationary, the other component is made to movetowards or away from the point of highest flux density depending on therespective polarities of each. A small coil can, for example, act on alarge set of permanent magnets to produce a wide stroke relative to thelength of the permanent magnetic plunger moving therein. This stroke canbe many times (e.g., 2-5 times) the length of the electromagnetic coilacting on it. In this example, the permanent magnets in the plunger maybe arranged or attached such that there is a separation between magnetsof various lengths.

Such embodiments can also, for example, enable production of a linearmotor capable of continual acceleration of the magnets. When this formof linear motor is carrying a load attached to a plunger, the load andplunger can be accelerated down a series of aligned coils. When the loadand plunger reach a desired position, the nonuniform magnetic fieldgradient can be used to gradually decelerate the plunger in motion byreversing the polarity of the coils acting on the load and plunger. Inembodiments, smoother deceleration can be attained using coils thatthemselves possess a nonuniform magnetic field gradient along theircentral axis. In embodiments, deceleration can also be attained whencoils are turned on at a time so as to attract the peak magnetic fielddensity of the plunger in motion in an opposite direction relative to acurrent direction of travel. Additionally or alternatively, inembodiments, a repelling action or force on the plunger in motion from acoil ahead of the plunger in its direction of travel. Thus, a method ofboth acceleration and deceleration may be enabled with this form oflinear solenoid actuator or motor. Optionally, the solenoid actuator canfurther include or be configured for communication with a positionfeedback mechanism or position sensor(s) and a controller capable ofturning power flow on and off to each coil based on a position of theplunger to selectively generate either acceleration or decelerationthereof (such as those discussed below with reference to FIG. 14). Insome implementations, positional holding or control can be possible whencoils acting on the plunger do not turn off, but instead maintain low acontinual power flow. Diagrammatically this set up may take a formsimilar to the embodiments shown in FIGS. 2A and 2B, where multipleactuators of similar construction may be on a single axis of movementwith a spacing of, for example, 1 mm between each respective actuator.

Two or more plungers being acted on by co-linear solenoid actuators orlinear motors possessing a nonuniform magnetic field can be connectedusing a rigid or semi-rigid member, which may result in higher totalforce production, as illustrated in the embodiment of FIG. 9. Thedistance between each of the sources of nonuniform magnetic fieldsdriving the solenoid actuators may be such that there is minimalinterference in the produced magnetic fields. One or more of theco-linear actuators or motors can be configured for reversal of polarityand include a mechanism for adjusting power flow thereto. This canenable production of counteracting forces on the rigid or semi-rigidmember connecting the plungers of the solenoid actuators and allow forvarious positions along the stroke pathway of the plungers to be reachedand held. Specifically, in the exemplary embodiment of FIG. 9, a rigidor semi rigid member 901 splits into two elbows 902 in order to connecttwo permanent magnets 903 which may act as the plungers in a solenoidactuator 900. Two coils 904 and 905 are constructed to produce anon-homogenous magnetic field which preponderates toward opposite ends,illustrated in that coil 904 is facing the opposite direction relativeto coil 905. As power is applied to these two coils 904 and 905simultaneously, the plungers 903 are both imparted a force which may actin opposite directions. As the average power in each of the coils isaltered, the position of the two plungers can be altered or changed.Maximum force in a given direction is achieved when the two coils 904and 905 are imparting forces on the plungers 903, which are acting inthe same direction. Further, any number of coils and plungers may, inthis fashion, be connected together with the added benefit of increasingthe actuation power. It may be especially advantageous in embodiments orapplications where precise control is desired over a wide stroke when,for example, additional solenoid coil(s) and plunger(s) are added to thesystem which have a displaced position of either the coil or plungerwith respect to the other coils and plungers in the system. Theseadditional components may allow for forces to be imparted on theplungers through their connection member (such as, the rigid orsemi-rigid member 901) while they are at the end of their stroke wherethe forces acting on them are otherwise negligible.

In additional or alternate embodiments, a solenoid actuator or a linearmotor configured to generate a nonuniform magnetic field gradient canhave at least two coils configured for acting in opposite directionswith at least one of the coils being connected to a circuit with amechanism for power mitigation for positional control. Additionally, inembodiments, an on/off switch can be included in each of the circuitsconnected to the electromagnetic coils for the purpose of selectivelyturning off the power flow and allowing the other coil(s) of theactuator to take over acting on a plunger. When two or more counteracting coils are used in a solenoid actuator, such switches can permit afull stroke or nearly full stroke of movement in each direction along alinear pathway (via e.g., turning individual circuits off), as well asenable the ability to perform discreet actions of small incrementalmovements (via e.g., power flow control to the individual circuitscontrolled by a controller such as, the computerized controllerapparatus 1410 discussed below with reference to FIG. 14). An example ofthis is shown in the embodiment of FIGS. 8A and 8B.

In additional or alternate embodiments, an electromagnetic spring can beformed when a coil has a larger number of windings at each end thereof.Such coil geometry can create a bipolar non-uniform magnetic field,which can have a stronger magnetic force acting on a plunger as itstrays from the midpoint of the coil. When at either of the end points,the plunger in motion (which may be a magnetic, ferromagnetic, orelectromagnetic object) can be forced to change directions. The plungermay experience forces that arrest its momentum and then return theplunger to the midpoint. Mounting forces towards the ends of the coil inthe solenoid actuator can allow for this to be done in a more effectivemanner relative to a conventional solenoid actuator. Not only can theplunger experience a returning force that draws it toward the midpointof the coil from the magnetic equilibrium that exists there, but theplunger can also be acted on by the nonuniform magnetic field, whichitself can cause motion in electromagnetic systems. It will beappreciated that similar result can be achieved via an actuatorembodiment including multiple coils aligned on a similar axis (such asthe solenoid actuator 300 illustrated in FIGS. 3A and 3B) when a greatercurrent density is applied to the coils at opposing ends of theplurality of coils. An exemplary embodiment of this may be nearlyidentical to the embodiment of FIGS. 8A and 8B except that the twocircuits may be joined by one power source such that the field producedby both sets of coils is additive.

As discussed above, in embodiments, a coil can have one or more adjacentcoils, which also have power flowing therethrough, which can, byapplying differing the power levels to the coils, alter their respectiveinfluences on a plunger (e.g., a magnetic or paramagnetic object orobjects). However, in alternate embodiments, a more potentially morecost-effective method of controlling the position of a plunger in asolenoid actuator or a linear motor having a plurality of coils can beconfigured to have an increasing number of windings and/or coils towardone end of the solenoid actuator or increasing power flow toward one endof the solenoid actuator. In such embodiments, variable power sourcessuch as, for example, a battery and a potentiometer, can cause a plungerin the system to have a varying amount of attractive or repulsive force,which can drive movement to a new location. Automated control of thesolenoid actuator can be made, for example, by attaching a motor to thepotentiometer and driving the motor from a computerized controller (suchas, the computerized controller apparatus 1410 discussed below withreference to FIG. 14) capable of causing incremental changes in aposition of the motor. In implementations, separate batteries ofdifferent power ratings can be connected to the circuit(s) withswitches, which may be controlled using the computerized controller. Itwill be understood that other types of variable power supplies andmethods such as pulse width modulation can be used in combination withthe actuators disclosed herein, and the disclosure is not limited to theabove examples. An example of this type of actuator is illustrated inthe embodiment of FIGS. 8A and 8B.

In embodiments, in order to add non-linearity to the magnetic fluxdistribution, the material of the coil's core may be altered. A core ofa coil can contain a material that increases inductance of the coil. Thematerial can be used to influence the inductance of some windings in acoil more than others. For example, when a solenoid actuator comprisingnonuniform magnetic fields along the stroke is comprised of two or moreelectromagnetic coils acting on one another, it may be desirable for thecoils to be similar in configuration to coils in a conventional solenoidactuator, but to include a core composition in a section of the windingsincluding a material (which may, for example, be ferromagnetic) in orderto increase the inductance of some windings relative to others of thewindings. For example, the coil can be configured to have more of theinductive material in windings at one end of the coil relative to thewindings at the opposing end of the coil. Such a configuration canincrease the non-linearity towards one side of the coil (i.e., a side ofthe coil having the inductive core) in order to increase the strokelength of the coil.

In an illustrative example, a cylindrical dowel that can be hollowed outin a manner that leaves more volume on one end with relative to theopposing end. The hollowed space can be filled with a material that iscapable of influencing the inductance of the nearby windings such as,for example, ferrite powder. A coil can then be wound on top of thedowel. The coil can thereby be configured to maintain an asymmetricalflux density along its length without the use of different coilgeometries or multiple circuits. In embodiments, primary coils withcores having such a configuration can have separate, secondary coilsmoving outside of them (such as, on the top of the primary coils) whilethe primary coils are held stationary. Such coils may also produce amagnetic field with asymmetrical flux density in other to furtherincrease the stroke distance of the solenoid actuator. Further, inembodiments, coils and/or magnets that may or may not produce fluxdensities that vary over their lengths can be acted on by another coilor magnet, which itself produces a non-uniform magnetic field density inorder to increase the stroke of movement of an object (a plunger) inmotion through a solenoid actuator. For example, as depicted in FIG. 10,a cylindrical coil core 1001 has a portion 1002 of its that is volumehollowed out and filled with a material of a different magneticpermeability than the rest of the core (illustrated in cross hatching).The whole core 1000 can then be utilized to wind a coil over. Inembodiments, the coil can then produce a nonhomogeneous magnetic fielddue to the magnetic permeability changing over the length of thecylinder 1000. This magnetic field may then be acted on by a permanentmagnet, which may be ring-shaped so as to travel along the length of thecoil that is wrapped on the core 1000. The coil and core may also be theplunger in an actuator system when the other source of a magnetic fieldacting on it is held stationary. Accordingly, a coil wrapped upon a coresuch as this acts in many ways like the magnetic field produced fromother embodiments such as that depicted in FIG. 2A.

In another embodiment, a solenoid actuator can have multiple taps alongits length similar to an autotransformer. The foregoing solenoidactuator can be configured for use with a power source and a controller(such as, the computerized controller apparatus 1410 discussed belowwith reference to FIG. 14) to create non-uniform magnetic fields for thepurpose of increasing the stroke in one or more coils of the solenoidactuator. A first end of a coil may be connected to the negativeterminal of a first battery, and a second opposing end of the coil canbe connected to the positive terminal of the first battery so that thebattery supplies power to the length of the coil. A first tap that is,for example, one third of the way down the length of the coil from thefirst, can be connected to a positive terminal of a second battery, andthe negative terminal of the second battery can be connected to thenegative terminal of the first battery. Accordingly, the second batteryprovides power flow through the corresponding one third of the coil,which is in addition to the power flow therein provided by the firstbattery. A second tap may be, for example, two thirds of the way downthe coil from the first end. The second tap can be connected to apositive terminal of a third battery. A negative terminal of the thirdbattery can be connected to the same terminal that the other batteriesare grounded through, therefore the third battery's power flow iscontained within two thirds of the solenoid length. This embodiment of asolenoid actuator can therefore comprise three distinct current flowsover the coil as each of the three batteries operates in a commensuratefashion over a respective portion of the coil across which it isconnected. In this exemplary embodiment, a single layer coil can beconfigured to generate a non-uniform magnetic field distribution using apower source (e.g., three batteries). In some implementations,additional switches can be configured to switch the polarity of each ofthe batteries so as to reverse the forces in the system acting on aplunger. Further, in additional or alternate implementations, byincorporating methods of controlling the power flow out of each battery(such as, via a connection through a potentiometer and another on/offswitch), fine tuning of the plunger's position may be possible. Forexample, FIG. 11 illustrated a solenoid actuator 1100 that possesses ofa coil with a construction very similar to that of an autotransformerexcept that it can be configured to produce a nonhomogeneous magneticfield along its length. The coil 1104 can have multiple taps along itslength 1103 a, 1103 b, and 1103 c between which power is distributed ina non-linear fashion. The power sources 1101 and 1102 can have differentnumbers of power cells that are configured to cause more power to flowbetween taps 1103 b and 1103 c than there is power flowing between 1003a and 1103 b. This produces a magnetic field density that varies alongthe length of the coil 1104. In alternate embodiments, a greater numberof taps can allow for a finer adjustment of the magnetic field densitygradient which exists along the length of this coil. Variable powersources which alter the average power through a given section canprovide a mechanism to alter a plunger's position within the coil,especially when the plungers position is being monitored and/orcontrolled via a controller (such as, the computerized controllerapparatus 1410 discussed below with reference to FIG. 14), and wheredata is used to control or vary the average power through the varioustaps on the coil 1104.

Furthermore, in additional or alternate implementations, the foregoingembodiment of a solenoid actuator can include a core within the coilthat is configured to enable a changing or variable magneticpermeability and/or distance from the coil to the core along the lengthof the coil. This can allow for a single coil to create an asymmetricalmagnetic field density on a surface of the coil by augmenting theinfluence of the core to the coil's inductance at various points alongthe length of the coil. A plunger can therefore move over the surface ofthe coil (e.g., over the top of the coil) in a similar manner to themotion of the plunger in other embodiments, wherein the plungerexperiences a force that drives it towards or away from the point ofhighest magnetic flux density, depending on the polarities of theplunger and the coil. The asymmetry in this example may also increasethe stroke of the solenoid actuator so long as the inductancepreponderates from one end of the coil to the opposing end. Such anembodiment can be useful in applications where a plunger moves over thetop of a solenoid since the coil may be linearly wound and have onecircuit, which therefore enables the distance between the plunger andthe coil to be minimized and the simplifies the construction of thesolenoid actuator.

Turning now to FIGS. 4A and 4B, a linear actuator 400 including aconical object 401) is depicted therein. As shown in FIG. 4A, theconical object 410 is can be comprised of metal and can include a hollowmetal tube 402 disposed therein and aligned with a central axis of thecone. FIG. 4B depicts the conical object 401 as it slides along incontact with an electrified rail 408 towards a plurality of insulatedelectrified rings 409, which can have an opposite electric polarityrelative to the conical object 401. The insulated electrified rings 409can be connected to a voltage source 403 in a manner that enables eachring to have a different voltage potential. The voltage potentials maybe dependent on, for example, a number of batteries (e.g., batteriesV₁-V_(n)) connected to the linear actuator 400 and/or their respectiveproperties. A non-uniform magnetic or electrical field can be generatedwhen the rings 403 create a non-linear function of forces based on, forexample, their respective voltage potentials and/or their distances tothe conical object 401 as it moves along the rail 408. A capacitivenature or relationship may exist between the rings 403 so that as theconical object 401 approaches them, arcing is limited and a differencein electrical potential exists between the respective ring 403 and theconical object 401. The electrical potential is positive on one side 404of the power source and negative on the other (opposing) side 405 when aDC power source such as a battery is used. A circuit 406 can be formedwhen motion results in closing of a switch 407. Such motion can be aresult of the nonuniform fields generated by the conical shape of theconical object 401 and its attraction to the insulated rings 403. Energyis, in this exemplary embodiment, can be drawn from the batteries andcan be consumed via a capacitor with an imbalance of forces acting uponit due to the conical shape of the conical object 401. Motion energy canbe further aided by the use of high voltage sources of electricpotential.

In one exemplary application, an object that is intended to accelerateincrementally, such as a linear actuator moving a delicate object wheresudden changes in the forces create impulses which are undesirable, canbe implemented using a configuration similar to the linear actuator 400(or configurations similar to other linear actuators disclosed herein),as force therein may be a product of factors such as the field densityand the current at a given point along the stroke. As these factors canbe made to vary with an asymmetrical distribution, naturallyincrementing speeds are possible. The acceleration curves of objects inthe system can be tailored to the application, for example, an inversesquare curve can be utilized and efficient results. An exemplary curve1200 is depicted in FIG. 12 where either the electric or magnetic fields(depending on the embodiment) are varied with respect to distance by theinverse square function.

In another exemplary application, objects that are in rotation orpivoting around a joint can utilize asymmetrical field distributionsalong the stroke for the purpose of increasing the stroke (discussed indetail below with reference to FIGS. 5A and 5B). In this example,asymmetrical distributions of magnetic field density or current densityof the stator, rotor, or both can result in motion of an object. Unlikeconvention actuators, the exemplary applicant can exclude motors and/orgears and instead use solenoid interaction, which may enable simplerand/or less expensive manufacturing. For example, in a rotating jointwith a direct current application, the motion can cease when the coil(s)with the highest flux density acting on a system with non-constant fluxdistribution of the object in motion aligns with the point of highestflux density on a stationary portion of the system. The embodiment canalso be applied to a motor if the stationary portion of the system,namely a coil acting on the system, is pulsed or switched offincrementally (for example, from a commutated connection like acommutated DC motor) when the point of highest flux density of thestationary and moving portions of the system align. As the alignment ofthe stationary and moving portions of the system can ordinarily causethe cessation of movement, a constant rotation can be produced byturning the coils off during this part of the rotation. Inimplementations, the rotating member may have springs attached to returnthe object in motion back to a previous (e.g., initial) position whenthe power level is changed, thereby enabling an object to rotate up tonearly one revolution before stopping when it is exposed to a nearbymagnetic field. In rotating actuator systems such as these, theasymmetric distribution of magnetic force along the axis of rotation canlead to vibration at higher RPM. In implementation, the vibration can bemitigated by placement of counterweights on the rotating body. Inadditional or alternate implementations, vibration can be mitigated byusing several similar arrangements (one next to the other) on a sharedrotating body where each arrangement of coils or permanent magnets is ata different point in its acceleration curve from coil or permanentmagnet located next to it.

In embodiments, rotational solenoid actuators configured to generate anonuniform magnetic field gradient for the production of motion cancomprise two coils of different polarity and/or winding direction, whichare positioned near each other. This can allow for a permanent magnet orelectromagnet to have each pole acting on or interacting with one of thetwo coils concurrently for more efficient force production through thesimultaneous utilization of both magnetic poles. An exemplary embodimentof a form of winding for coils that produce a nonuniform magnetic fieldgradient along the diameter of a rotational linear actuator can beachieved via, for example, having multiple coil bobbins extendingradially out of the actuator, which may be non-magnetic. Further, a coilcan be wound such that two or more neighboring bobbins have a windingwrapped around them with a next winding wrapping around fewer bobbinsthan the preceding winding, until a winding is wrapped around a singlebobbin. In embodiments, the progressive wrapping around fewer bobbinsuntil reaching the single bobbin can be repeated one or more times withthe same wire or an attached wire. This coil geometry can generate anonuniform magnetic field that is progressively greater as it approachesthe coil bobbin with the most windings around it and may act on one poleof a permanent or electromagnetic source. In embodiments, this form ofcoil may have a neighboring coil of the same geometry to act on theother pole of the permanent or electromagnetic source, which can, asdiscussed above, result in increased efficiency of the rotational linearactuator. This geometry is related to the embodiments of FIGS. 8A and8B, as well as the exemplary rotational actuators of FIGS. 5A-5C.

FIGS. 5A-5C depict an exemplary embodiment of a rotational actuatorapparatus 500, which is designed to actuate a rotating member 501. Therotating member 501 can be configured to rotate around a central axis ofrotation 511 through the interaction of a first magnetic field aroundthe rotating member 501 with a second magnetic field generated by aseparate coil 507 when one or both of the first or second magneticfields is a non-linear field gradient in the direction of rotation. Inthis embodiment, the magnetic field around the rotating member 501 iscan be a source of a nonuniform magnetic field due to geometry of itscoil 504. In implementations, the coil 504 is segmented in aconfiguration that can generate a peak magnetic flux density toward oneend of the coil 504 and a minimum flux density on an opposite endthereof. The coil 504 can be connected to a power source 503 throughconnecting wires 504 and 504 a. Similar to the rotation linear actuatordescribed above, the coil 504 is wound around a plurality of bobbins 505a-505 e so that a number of windings around the bobbin 505 a is greaterthan the number of windings around the bobbin 505 b. Further, a numberof windings on each subsequent bobbin is less than the preceding bobbin(for example, the bobbin 505 a has a great number of windings than thebobbin 505 b, which has a greater number of windings than the bobbin 505c, which has a greater number of windings than the bobbin 505 d, whichhas a greater number of windings than the bobbin 505 e). Thisconfiguration results in a single coil (i.e., the coil 504) configuredto generate an area of peak magnetic field density that is displacedrelative to the center of the coil (i.e., towards one end of the coil507). The separate coil 507 is connected to a power source 508 through aswitch 509 (in FIG. 5A the switch 509 is shown in an open position 509a). The coil 507 can be configured to generate the second magnetic fieldfor interaction with the first magnetic field generated by the rotatingmember 501 so as to rotate the member 501 towards a point (e.g., aposition of 505 a) where the peak magnetic field lines up with thestationary magnetic field of the coil 507. The side elevation view ofFIG. 5B depicts a side view the rotational actuator apparatus 500including an actuator 502.

FIG. 5B depicts a side view of the rotating member 501, illustrating thegeometry of the coil 504. As can be seen therein, each consecutivewinding is wrapped around on consecutive ones of the bobbins 505 a-505e, thereby resulting in each winding being different distance from thefirst bobbin 505 a. Further, the configuration results in the bobbin 505a having the most windings (the greatest number of windings) in contacttherewith, and therefore is the location of greatest magnetic fielddensity is in the area of the first bobbin 505 a.

FIG. 5C depicts the rotating actuator 500 after the switch is moved to aclosed position 509 b causing rotation of the rotatably member 501.Specifically, the rotatable member 501 can be rotated such that the peakmagnetic flux density (located at the bobbin 505 a and corresponding toa magnetic north pole of the coil 504) is aligned with a magnetic southpole of the coil 507. The direction of rotation 512 about the centralaxis 511 depicts the movement that occurred after or when switch 509 isin a closed 509 b.

In implementations, this embodiment can include a spring within therotating member 501, which can enable actuation which returns an objectto a predetermined position without switching the polarity of the coil507. In such implementations, a distance of rotation of the rotatingmember 501 can be controlled (and varied) by selecting specified powerlevels that partially overcome the spring's tension, which may beselected via e.g., a controller apparatus (such as the computerizedcontroller apparatus 1410 discussed below with reference to FIG. 14).Alternatively or additionally, the actuator 500 can include a flexiblecable, which may be the moving object in the system. The flexibility ofthe cable allows for of the actuator to be used for variousapplications, especially those in which the flexibility is needed orbeneficial. Examples of where flexibility may be beneficial may be wherea moving object in the system needs to make a turn, such as in e.g.,clothing or some robotic systems. In such instances, the flexible cablecan form a non-linear central axis of actuation. An example of thiswould be the addition of a spiral spring to the actuator apparatus 500of FIGS. 5A, 5B, and 5C. For example, a spiral spring may be rigidlymounted on a stationary member on one end and attached to the rotatingactuator on the other. Turning off the power or reducing the averagepower may allow for the rotating object to completely or partiallyreturn to a predetermined position. Further, the spring may be designedto take the rotating member from the end of the actuation stroke to thebeginning so that it may be acted upon by the coil without a polarityreversal being necessary.

In other implementations, the actuator 500 can be used in combinationwith hydraulic or pneumatic actuators to increase a force produced bythe combined actuator and/or reliability of the combined actuator. Forexample, during use, strain may be lowered on one or more components ofthe system. In another example, one actuator may act as a backup to theother actuator in an instance where one fails.

In still other implementations, the actuator 500 can be used in voicecoil actuators in conditions where an asymmetrical field density may bedesirable. The asymmetrical field density actuator may be simpler tooperate than a conventional voice coil type due to the ability to use DCfrom more simple power sources and to make the object or plunger inmotion perform a variety of movements, such as omni and/orbi-directional movements. It may also be possible to produce theasymmetrical field density solenoid actuator in a lower cost manner thana typical voice coil., and/or in other applications related to vehicles,including in internal combustion engine valves, fluid pumps, fluidvalves, oscillators, projectiles, automatic surface leveling, and/or insuspension systems. The form of the actuator may take that of theembodiments of FIGS. 2A and 2B.

The rotatable actuator 500 (as well as other actuators disclosed herein)may be more compact for use in a given application relative toconventional actuators. Further, the rotatable actuator 500 (as well asother actuators disclosed herein) may reduce a gap in time within whichthe object in motion receives little or no driving force (due to itsposition coinciding with either peak or minimum magnetic flux density)when there are multiple coils along a single axis. In contrast, inconventional actuators, an object or plunger can only travel in onedirection and may be acted upon by multiple co-axial coils as the coilsswitch on and off as the object reaches the halfway point along thelength of a respective coil. The asymmetrical field density design ofthe actuators disclosed herein may address these issues. In theembodiments of FIGS. 5A, 5B, and 5C, this would take the form of one ormore additional coils similar to coil 507.

FIGS. 5A, 5B, and 5C can represent an embodiment of an axial fluxactuator. Although this design of an axial flux actuator takes placearound an axis of rotation, the same actuator can function in a linearmotion application as well. This may be advantageous in applicationswhere the plunger and the coils are not required to be constrained bythe solenoid windings being wrapped around the outside of the plunger orwith the plunger being positioned on top of the solenoid windings. Itmay also be advantageous to adopt this form of linear actuator whenspatial constraints limit the length of the rigid or semi rigid piecewhich connects the object which needs motion imparted to it and theplunger of the actuator. This reduced spatial constraint is the resultof the configuration of the coil windings. Further, both poles ofpermanent magnets may be used to act on both poles of the magnetic fieldproduced by a coil wound in a manner similar to that of the embodimentof FIGS. 5A, 5B, and 5C.

In other embodiments, pulsed DC can be used in combination withactuators configured to disclosed herein for thermal management.Additionally, the actuators disclosed herein can be used in combinationwith housings having cooling systems embodied as metal vanes or hollowbodies containing the coil(s), which are equipped for cooling fluidbeing pumped therethrough.

The actuator, rotating joint, or motor may also have provisions forlocking in place. This allows for no energy to be consumed when theactuator is holding a predetermined position.

It will be appreciated that the components of the actuators disclosedherein can be implemented in forms other than linear and rotationalactuators. For example, other magnetic systems of force can may beconfigured to include features of the actuators disclosed herein inorder to implement non-linearity which can aid in the duration ofapplied forces, as well as tailoring of the slope of the forces. Sinceeach subsequently peripheral coil adds onto the field of the coilbeneath it, a function of combined or additive forces (i.e., the sum ofeach of the individual coil's forces) may be formed by the system. Asmore non-linearity is introduced into a coil system design, thegenerated magnetic field and the subsequent force profiles follow suit.

Further, the profile of the non-linearity of flux potentials can besuited to the application for which the linear actuator (or anotheractuator) is required. For example, it will be appreciated that acertain function of flux density distributions may be especiallywell-suited to an application, and the distribution can take the form ofthe inverse square curve (i.e., 1/d{circumflex over ( )}2). Variousother flux distribution patterns may be used where applications desire aparticular profile of forces on an object or plunger in motion. Aspecific example of an application where this trait may be desirable oruseful is with an object that must be made to resist certain strains asit is actuated, where these strains do not increase in a linear mannerbut are instead varying in an exponential manner over the stroke ofactuation.

Another feature of disclosed herein can be gradual and successivelygreater acceleration that is experienced by a moving object or plunger.The successive accelerations progressively stacking up may yield agreater efficiency of force transference onto the object or plunger thana strong impulse of force of a constant amplitude. The added efficiencycan be gained by the integral of the acceleration function being largerthan a comparable coil. The reason for this increase in efficiency mayat least in part be due to fact that the limits of the function ofapplied force are twice that of an ordinary coil since the object orplunger is capable of being acted upon for nearly twice the amount oftime while it is within the primary coil.

In applications where optimum efficiency is desired, the linearactuators or other actuators disclosed herein can be provided withcoils, which are wound in a bifilar fashion in such a way as to increasethe field density of a coil for a given number of turns as is described,for example, in the U.S. Pat. No. 512,340, which is incorporated byreference herein. This can allow for less materials to be used in thecreation of an actuator of a certain desired force. A further increasein efficiency can be made by distributing the field density in a mannerthat corresponds to the inverse square law, thereby imitating thenatural magnetic field distribution of a permanent magnet.

FIGS. 7A and 7B illustrate a linear actuator 700 that includes a magnet701 (comprising of a series of permanent magnets 701 a, 701 b, 701 c,701 d) configured to produce the asymmetrical flux density, wherein acoil 703 with electric potential is applied to the linear actuator 700to produce motion of either the permanent magnets 701 a, 701 b, 701 c,701 d or the coil 703 itself. As can be seen in FIG. 7A, the cylindricalpermanent magnets 701 a, 701 b. 701 c, 701 d can each have a differentdiameter and connect together so as to form a single magnetic dipole.The variation in diameter can augment the magnetic flux densityexperienced by the coil 703 from the magnet 701 in such a way as tocreate a nonuniform magnetic field along its length. A circuit 705 incommunication with a current source and a switch 706 can allow thestationary coil to act on the magnet 701 so as to produce a linearactuator with a wider stroke (relative to a conventional linearactuator) as a result of the augmented profile of the magnetic fluxdensity along the permanent magnet's length.

FIG. 7A illustrates the switch # in a closed position 706, while FIG. 7Bdepicts the linear actuator 700 in a state where the switch 706 is in anopen position 706 a and is moved into a closed position 706 b. When inthe closed position 706 b, power flowing through the coil can act uponthe magnet 701 and causes them to move nearly the full length of the waydown the coil 703. A South pole 708 of the magnet 701 can extendoutwardly from front of the end of the coil 703 after the magnet 701 hasmoved its full stroke, and the North pole 702 can be aligned with theback end of the coil 703.

Without departing from the scope of the present disclosure, a toroidalcoil could be used in the linear actuator 700, which may employ a core.The toroidal core may be beneficial when ultra-fast movement is desired,on account of the inherently higher quality factor, which make thempredisposed to fast switching of polarity or power levels. Additionally,or alternatively, Litz wire may also be used to this end. Thediagrammatic representation of this may not depart from the embodimentshown in FIGS. 7A and 7B, where the coil is a toroid instead of anordinary solenoid.

In order to lower the weight and/or the cost of the linear actuator 700,the magnets 701 a, 701 b, 701 c, 701 d can be connected with iron rods,which may be hollow to create a virtually longer permanent magnet.Additionally or alternatively, electromagnetic solenoids can be used inplace of the permanent magnets (with or without magnetizable cores). Forexample, the electromagnetic solenoids can be of classic construction orasymmetrically constructed to suit a particular force profile of theapplication. In implementations, longer life due to a lack of magneticforce deterioration found in permanent magnets may be provided at theexpense of power consumption when EM solenoids are used in place ofpermanent magnets in the actuator 700.

Turning to FIGS. 8A and 8B, a linear actuator 800 is shown anddescribed. In applications where precision of movement is desired, twocoils may be used, which are oppositely magnetized. In such aconfiguration, the power of each coil can be biased so that one coilpredominates using electric control systems capable of intelligentcomputation of movement and precise actuation of power (such as, thecomputerized controller apparatus 1410 discussed below with reference toFIG. 14). Such control systems are known use in screw type actuators.The coils can be on different axes of movement and can be connectedtogether through a rigid or semi-rigid mechanism to prevent thedistortion of their respective fields.

FIG. 8A the linear actuator 800 includes a first coil 820 a comprisingthree sets of windings 801, 803, 805 on a first circuit and a secondcoil 820 b comprising three sets of windings 802, 804, 806 on a secondcircuit, which are each disposed along a single axis 807 and configuredto act on a plunger. Specifically, the first and second coils eachconsist of an inner winding 801, 802 that stretches the full length ofthe actuator 800, an intermediate winding 803, 804, and an end winding805, 806. Two non-uniform magnetic fields can be created utilizing thelinear actuator 800, which have their peak flux density at oppositesides of the coils. Each of them can act on a plunger in such a way thatthe coils push or pull on it simultaneously.

FIG. 8B shows the foregoing coils (circuits) 820 a, 820 b each connectedto a power source 808, 809, and each with a potentiometer 810, 811,which can be used in the actuator 800 to augment the power flow of eachcoil. This can enable biasing of the forces acting on a plunger in orderto augment the stopping position of the plunger along the stroke. Asdiscussed above, each coil 820 a, 820 b consists of three sections orgroups of windings, where, in addition to having different length, thesections of windings have different diameters relative to other sectionsin the coil, as each section of windings is wound over the previousgroup of windings. When the potentials of one or either coils 820 a, 820b are augmented, it can cause the plunger(s) in motion to be attractedto one end or the opposing end of the actuator 800 in proportion to theratio of flux density produced between the two coils. It will beunderstood that other configurations and/or methods of altering the fluxdensity of one or both of the coils 820 a, 820 b may be used, such asincluding and utilizing a variable power source. In examples, a selectedratio of flux density can be used to control power delivery to one orboth of the coils 820 a, 820 b via a controller apparatus (such as thecomputerized controller apparatus 1410 discussed below with reference toFIG. 14), which can be further utilized to control a position of theplunger(s). It will be further understood that the direction of windingof the coils and the manner of application of electric potential can bereversed without departing from the resulting motion that is produced.

It will be yet further understood that heat generated by a coil or coilsin the linear actuator 800 (or other actuators disclosed herein) givingrise to nonuniform field distributions may be greater where the fielddensities are greatest. Accordingly, in implementations, enclosures forcooling fluid to flow through may be incorporated into the actuator.Similarly, in alternate or additional implementations, vanes can beused, which may be longer at the points of greatest field density, toaid in the cooling of the coil(s). Further, in additional or alternateimplementations, watertight enclosures may be used for a givenapplication. Pulse width modulation may be used to alter the position ofthe plunger through its application to one or both circuits.

In implementations, the linear actuator 800 (or other actuatorsdisclosed herein) can be used for the gradual absorption of high impulseforces. A permanent magnet (plunger), which is made to move through acoil that includes progressively more or layered windings, mayexperience a progressively increasing reluctance to movement from theincreasing back-EMF. This may be similar to compression of a springexcept that the energy is not stored kinetically through tension, thoughit may be generated and stored electrically depending on theconfiguration of the impulse absorbing apparatus. For example, oneconfiguration may have a coil actively resisting the motion usingelectromagnetic fields produced by a power source, whereas anotherconfiguration may have a passive coil where the permanent magnetencounters a greater back-EMF as it travels along the length of the coilcontaining more (or less) windings toward one pole or one end thereof.The latter configuration may provide an electrical generating potentialand the former may provide greater force retardation of the movingplunger. High impulse forces may therefore be absorbed and the densityof the windings along the coil can be tailored for gradual slowing ofthe plunger, which would otherwise experience a more rapid decrease inspeed, and thereby lower the force impulse. Another example of impulsereduction may be a configuration where a coil with nonuniform fluxdensity is energized and a soft iron bar (plunger) is imparted someforce as it moves through the coil. In this example, the coil may resistthe movement of the iron bar proportionally to the field at a givenpoint. As the field is not linear, the force may experience a changingreluctance of movement, which may lower the impulse curve of the forceon the bar. In implementations, multiple coils with variable powersources can be used to change the gradient of the magnetic field tofurther tailor the reluctance to the force imparted on the magnetizedobject (plunger) in real time. Further, the coils may be configured in away in which an impact triggers a circuit to turn on through thephysical shock or through the dislodging of an object that was breakingthe circuit. Multiple such objects can be used for multiple circuits.The form of this embodiment may not depart from the form shown in FIGS.2A and 2B.

This type of actuator may be particularly well-suited to applicationswhere the force exerted on the actuator by a system is not constant. Anexample of this application includes, e.g., crushing of an object,stretching of an object with some degree of elasticity, and repelling ofa magnetized object from a single pole of a coil system.

In implementations, the linear actuator 800 (or other actuatorsdisclosed herein) can be used for the rapid movement and levitation ofmagnetized objects in space. For example, an object can be placed in aspace surrounded by an actuator that produces a magnetic field, such asbeing placed in one or more coils. The coils can be turned on and offwith a polarity and frequency corresponding to the object's position inspace in such a way that the object is attracted to a denser magneticfield in the direction of the desired trajectory of the object. Theobject may be, for instance, a spherical magnetic object suspendedagainst gravity with the north and south poles perpendicular to the pullof gravity. Multiple coils, which themselves may be comprised of one ormore individual circuits for further fine tuning of the field density(as in, e.g., the exemplary embodiment of FIGS. 7A and 7B), arepositioned around the object. As the spherical object fall towards thebottom of the actuator, a series of coils can produce fields that createa field density distribution that pulls both the north and south polesupwards. As the object rises, the coils can turn off, causing the objectto crest and fall. When the field gradient is not parallel with the pullof the object, a spinning of the spherical object can occur and asubsequent wobble of the object on its axis would occur. Provided thatthere is some mechanism for keeping track of where the object is inspace and where the poles are located, the forces from the coils cancontinue to keep the spherical object aloft. It will be understood thatthe object may be of any shape and it may be paramagnetic,electromagnetic, or contain permanent magnets. The magnets may have adesired distribution configured such that fields are created with amagnetic flux distribution pointed in the desired direction of travel.

In implementations, a computer can be utilized in combination with thelinear actuator 800 (or other actuators disclosed herein) to predict thetrajectory based on past or present locations and switch the power tothe coils accordingly to move the object (or plunger) in an intelligentway. Further, in implementations, more than one object (or plunger) canbe moved in this way provided that there is sufficient data collectedfrom the moving objects. A predictive model can be found, which allowsthe computer to operate independently of real-time position centersprovided it has the previous location data of an object. In examples,using this configuration multiple small objects can maintain an orbitaround a central magnetized object. The central object can include, forexample, multiple coils pointed in different directions radiallyoutward, each with individual circuits attached to a computerizedcontroller (such as e.g., a computerized controller apparatus 1410discussed below with reference to FIG. 14). Coils on the periphery canact on the moving magnetized objects to maintain spatial orientation. Inthis type of actuator, a model of planetary motion can be made whereelliptical orbits of the moving magnetized objects are brought aboutthrough the use of rapidly fluctuation magnetic fields withintelligently controlled field density altering the objects trajectoryby creating denser fields in the desired direction of motion. Bothattraction and repulsion can be used in such an actuator to cause thedesired motion. The objective may be to minimize distortion of therespective trajectories by keeping the moving objects polarity aimed inthe same direction throughout the course of movement. For example, amodel of a liquid vortex can be applied to the computer's trajectoryalgorithm since a floating object dropped into a liquid vortex pointsthe same direction continually as it swirls around the central axis.

In implementations, instead of using magnets in an actuator, whichcreates flux distributions to move objects intelligently in threedimensions, ionized particles and plasma may similarly be controlled.The electric field distribution may be augmented in suchimplementations. There may be little or no limit to color density and/orspeed of movement other than the strength of the field at a given pointin the designated space. For use with plasma, vacuum containers with amechanism for augmenting the potential dynamically at a given point andto high flux levels may be utilized for the maximum adjustability. Thisconfiguration and method can be used in the acceleration of particlesin, e.g., a particle accelerator. Sound waves may be incorporated to addanother layer of control to these actuators by creating compression andrarefaction, which may influence the ionized particles density. Anexemplary embodiment showing acceleration of ionized particles over awider length due to a nonhomogeneous electric field is depicted in FIG.13, discussed further below.

In implementations, the linear actuator 800 (or other actuatorsdisclosed herein) can be used for extension of the length of adielectric barrier discharge as, for example, in a plasma actuator. Adielectric barrier discharge can be increased in length by theapplication of nonlinear voltage distributions on a charged conductorthat is sheathed under a dielectric barrier. Plasma actuators, which usea dielectric barrier discharge in order to, for example, influence fluidflow of the surrounding medium, can by this method extend the influenceof the plasma on the fluid medium through the relatively longer lengthof travel, which the ionized plasma is made to be conveyed upon by theintroduction of the field asymmetry. The configuration and method forproducing the nonlinearity of the field in this example may be throughthe influence of mutual capacitance of a secondary source on thesheathed conductor. The mutual capacitance can cause a change in thecharge distribution along a surface of a conductor and therefore achange in the voltage distribution along the conductor. The secondarysource may provide a mutual capacitive influence over a small portion ofthe surface of the sheathed conductor when it is desirable to cause achange in the voltage distribution only over the small portion of theconductor. Multiple other voltage sources may be employed that may havedifferent voltage levels when it is desired for the dielectric barrierdischarge to have a particular or dynamic distribution of the plasmaalong the discharge axis. It will be appreciated that the mutualcapacitance in the system, which produces the nonlinear field, may be afunction of voltage and surface area, so either may be augmented tochange the field distribution. This is shown in FIG. 13 where a plasmaactuator 1300 is constructed of an upper electrode 1301 which is exposedto the flow of a fluid over its surface. A dielectric 1303 separatesthat electrode and a second electrode 1302 which is shaped so as toprovide an increasing electric field density to the ionized particlestraveling from the first electrode 1301 as they travel further over thesurface of the dielectric. This can increase the effectiveness of theplasma actuator in acting on a fluid medium by widening the plasmaactuators range of influence on the fluid body.

Alternatively, in implementations, one of the electrodes in the plasmaactuator can have multiple sections of the conductor separated by thedielectric (as the exemplary embodiment in FIG. 5). Each of theconductors may have a separate voltage from a suitable high voltagesource. The charge may be predominating in one direction. Accordingly,the dielectric barrier discharge may tend to redistribute its density tofavor the direction of the higher voltage conductor. The benefits ofthis implementation may include the functioning of a dielectric barrierdischarge plasma actuator at relatively lower fluid medium speeds andwith relatively higher efficiency, both of which may be a result of thelonger field of influence for a given plasma actuator. Further, it maybe applied to the exterior of vehicles or aircraft to influence the dragcoefficient more effectively through the creation of a larger field ofinfluence of the discharge and through the acceleration of the ionizedparticles in the plasma toward the higher density voltage conductor. Theextension of the plasma discharge can also be applied in other areas ofindustry, such as the sterilization of food and any other area wheredielectric barrier discharges are used. This embodiment is similar infunction to that depicted in FIG. 13 except that the curved electrode1302 can be replaced with a flat electrode which is parallel withelectrode 1301 and consists of multiple conductors of differentpotential in order to augment the electric field strength to increasethe length the ionized particles travel. This also increases theeffectiveness of the plasma actuator in acting on a fluid medium bywidening the plasma actuators range of influence on the fluid body.

FIG. 14 shows an exemplary embodiment of an actuator and controllersystem 1400. As can be seen therein, in embodiments, the system 1400 caninclude a solenoid actuator 1402 (which can be any of the actuatorembodiments and include any of the components thereof shown anddescribed in FIGS. 2A-13). The actuator 1402 is on one more electricalcircuits for communication with one or more power sources 1404 (such as,e.g., variable power sources), where closing and opening of theelectrical circuits are respectively controlled by one or more switches1406. The system 1400 can optionally include a position sensor(s) 1408configured to sense or identify a position of one or more plunger(s) inthe actuator 1402. Each of the switches 1406, the power sources 1404,and the position sensor 1408 can be in communication with one or morecomputerized controller apparatus 1410. The computerized controllerapparatus 1412 can include, for example, a communication interface 1412,one or more processors or microprocessors 1414 that comprise memory (ordata storage apparatus) 1416, and/or a graphical user interface (GUI)1418 configured to receive user input and/or display data to a user. Thememory 1416 can store one or more computer programs therein including aplurality of computer-executable instructions for operating orcontrolling the actuator 1402 to perform the various operations andapplications discussed above with reference to FIGS. 2A-13 and elsewhereherein.

In exemplary embodiments, the foregoing processors and/ormicroprocessors can include various types of digital processing devicesincluding, without limitation, digital signal processors (DSPs), reducedinstruction set computers (RISC), general-purpose (CISC) processors,microprocessors, gate arrays (e.g., FPGAs), PLDs, state machines,reconfigurable computer fabrics (RCFs), array processors, securemicroprocessors, and application-specific integrated circuits (ASICs).Such digital processors may be contained on a single unitary integratedcircuit (IC) die or distributed across multiple components. Further, inexemplary embodiments, the foregoing memory and storage devices caninclude various types of integrated circuit or other storage devicesadapted for storing digital data including, without limitation, ROM,PROM, EEPROM, DRAM, SDRAM, DDR/2 SDRAM, EDO/FMS, RLDRAM, SRAM. “flash”memory (e.g., NAND/NOR), 3D memory, and PSRAM. Furthermore, in exemplaryembodiments, the foregoing communication interface can be a signal ordata interface with a component or network including, withoutlimitation, those of the FireWire (e.g., FW400, FW800, etc.), USB (e.g.,USB 2.0, 3.0. OTG), Ethernet (e.g., 10/100, 10/100/1000 (GigabitEthernet), 10-Gig-E, etc.), MoCA, LTE/LTE-A, Wi-Fi (802.11), WiMAX(802.16), Z-wave, PAN (e.g., 802.15)/Zigbee, Bluetooth, Bluetooth LowEnergy (BLE) or power line carrier (PLC) families.

Additional examples of the disclosed technology are enumerated below.

1. An improvement to the length of stroke of systems of force productionthrough the use of magnetic fields through the introduction ofnon-linearity of the flux density along the length of the coil and alongthe length of a rod containing permanent magnets.

2. A method of displacing the point of centralized force within a coilor solenoid by changing the field density distribution.

3. An optimization of non-linear coil geometry for the application ofthe acceleration of a moving object by creating coils or the magneticfield of an apparatus in a non-linear shape.

4. A linear motion producing apparatus, which operates with thecapability of a longer stroke through the displacement of the point atwhich the balance of magnetic forces is achieved on a moving object inthe system with an application in linear actuators, linear motors,linear accelerators, mechanical oscillators, etc.

5. A method of tailoring the force profile in electromagnetic systems ofmotion including to motors, actuators, etc.

6. A system with a plurality of coils of asymmetrically oriented fluxdensities that are capable of individually biasing the electric power soas to allow precise actuation of a moving object. In this manner anydesired direction, speed, or distance of stroke of the linear actuatormay be provided.

7. A system comprising of variable magnetic density permanent magnetswhere an electromagnet or another permanent magnet is made to move alonga relatively longer stroke.

8. A system in which the tailoring of the force on an object isattainable through the manipulation of field density over the stroke ofsaid object, which may be non-linear, giving rise to non-linearacceleration profiles. These acceleration profiles and magnetic densityprofiles may advantageously include the inverse square curve, thehyperbolic curve, or a distribution that follows that of theBrachistochrone curve. The most efficient curve for force distributionis the curve that most closely represents that of the natural permanentmagnet, which is the curve made by the inverse square law.

9. A system in which the function of the increase in magnetic fielddensity of the coil system or the permanent magnets can be tailored toan application or altered for maximum efficiency.

10. Furthermore, the function of the increase in magnetic or electricfield density of the coil system, permanent magnets, or electric chargescan be tailored to an application or altered for maximum efficiency. Thehighest efficiency of operation would be given by a field in the shapeof the curve of the inverse square law.

11. A system in which the non-linearity of the forces in a system of alinear or rotational actuator comprising of non-uniform magnetic fieldscan be altered by the introduction of a source of tension (a rubberband, for example).

12. A system in which many additional systems of force can be attachedto the moving and stationary member(s) of a nonuniform fielddistribution actuator using rigid or semi-rigid means.

13. A system of movement, which can comprise a system of nonuniformfield distributions using no permanent magnets at all when a pluralityof electromagnetic coils are used.

14. A system comprising of one or more coils, magnets, electrostatic, orother sources of high electric potential with asymmetrically distributedflux fields that can be incapsulated in an air or watertight enclosure,without departing from the scope of the disclosed technology.

15. A system of non-linear flux density that can be made without usingstandard circular coil windings, and motion can be made to occur on anyother object, which acts on or is acted upon by a magnetic field.

16. Without departing largely from the scope of the disclosedtechnology, the electromagnetic coils and permanent magnets can bereplaced by electrostatic potentials with elements comprised ofincreasing flux densities on one direction, which can be acted upon byan object with an electrostatic charge or bias including electrets andcharged conductors.

17. A system that possesses asymmetrically dense flux fields, which canact in either attraction or repulsion in order to provide movement oractuation.

18. A system in which a linear actuator or linear motor may have onemoving part that travels nearly the full length of the actuating coil,reducing the redundant space of a common solenoid or voice coil, therebyoffering the possibility to do away with multiple moving parts.

19. A system where multiple permanent magnets of the same size and fluxdensity may be used in an ordinary geometry electromagnetic coil byaltering the distance of the permanent magnets to the coil in use overthe axis of the object to be set in motion.

20. A linear actuator comprising: a plunger, one or more first coilmembers circumscribing a central axis, wherein the one or more firstcoil members are configured to produce a first asymmetrical fielddistribution having a greater flux density at a first end of the linearactuator, and one or more second coil members circumscribing the centralaxis, wherein the one or more second coil members are configured toproduce a second asymmetrical field distribution having a greater fluxdensity at a second opposing end of the linear actuator, wherein the oneor more first coil members and the one or more second coil members arefurther configured such that the each of first asymmetrical flux densityand the second asymmetrical flux density is independently controllableto cause motion of the plunger along the central axis relative to theone or more first coil members and the one or more second coil members.

21. A linear actuator according to any of the examples disclosed herein,wherein the one or more first coil members comprises a first coil on afirst circuit, the first coil comprising two or more sections of firstwindings, each of the two or more sections of first windings at leastpartially radially overlapping with an adjacent section of firstwindings, the two or more sections of first windings configured suchthat there is a greater number of overlapping first windings distributedtoward the first end of the linear actuator relative to a center of thelinear actuator.

22. A linear actuator according to any of the examples disclosed herein,wherein the one or more second coil members comprises a second coil on asecond circuit, the second coil comprising two or more sections ofsecond windings, each of the two or more sections of second windings atleast partially radially overlapping with an adjacent section of secondwindings, the two or more sections of second windings configured suchthat there is a greater number of overlapping second windingsdistributed toward the second opposing end of the linear actuatorrelative to a center of the linear actuator.

23. A linear actuator according to any of the examples disclosed herein,wherein the one or more first coil members comprises a plurality offirst coil members each on a separate circuit, wherein each first coilmember comprises a portion of first windings that radially overlaps withan adjacent first coil member, the plurality of first coil membersconfigured such that there is a greater number of overlapping firstwindings distributed toward the first end of the linear actuatorrelative to a center of the linear actuator.

24. A linear actuator according to any of the examples disclosed herein,wherein the one or more second coil members comprises a plurality ofsecond coil members each on a separate circuit, wherein each second coilmember comprises a portion of second windings that radially overlapswith an adjacent second coil member, the plurality of second coilmembers configured such that there is a greater number of overlappingsecond windings distributed toward the second opposing end of the linearactuator relative to a center of the linear actuator.

25. A linear actuator according to any of the examples disclosed herein,wherein the one or more first coil members and the one or more secondcoil members are further configured such that the each of firstasymmetrical flux density and the second asymmetrical flux density areindependently controllable to stop motion of the plunger along thecentral axis relative to the one or more first coil members and the oneor more second coil members.

26. A linear actuator according to any of the examples disclosed herein,further comprising a first variable power source in communication withthe one or more first coil members, and a second variable power sourcein communication with the one or more second coil members.

27. A linear actuator according to any of the examples disclosed herein,wherein the linear actuator is configured for communication with acontroller, the controller in communication with and configured tocontrol power from a first variable power source to the one or morefirst coil members for production of the first asymmetrical fielddensity and control power from a second variable power source to the oneor more second coil members for production of the second asymmetricalfield density.

28. A linear actuator according to any of the examples disclosed herein,wherein the linear actuator is configured to be controlled such that,when more power is applied to the one or more first coil membersrelative to the one or more second coil members, the first asymmetricalflux density acts on the plunger to result in at least one of movementof the plunger toward the first end of the linear actuator or retardingmovement of the plunger toward the second opposing end of the linearactuator.

29. A linear actuator according to any of the examples disclosed herein,wherein the linear actuator is configured to be controlled such that,controlling a ratio of flux density of the first asymmetrical fluxdensity relative to the second asymmetrical flux density results incontrol of one or more of a speed of the plunger moving along thecentral axis, a position of the plunger on the central axis, a directionof movement of the plunger along the central axis, or a stroke length ofthe plunger along the central axis.

30. A linear actuator comprising: one or more first coil memberscircumscribing a central axis, and a plunger disposed at least partiallywithin the one or more first coil members, wherein the one or more firstcoil members are configured to produce a first asymmetrical fielddistribution having a first peak density toward a first end of thelinear actuator, and wherein the first asymmetrical field distributionis configured to have an increased maximum stroke length of the plungeralong the central axis relative to a coil having symmetrical fielddensity and a same length as the one or more first coil members.

31. A linear actuator according to any of the examples disclosed herein,wherein the one or more first coil members comprises a plurality offirst coil members each on a separate circuit, wherein each first coilmember comprises a portion of first windings that radially overlaps withan adjacent first coil member, the plurality of first coil membersconfigured such that there is a greater number of overlapping firstwindings distributed toward the first end of the linear actuator.

32. A linear actuator according to any of the examples disclosed herein,wherein the linear actuator is configured such that a polarity of eachof the one or more first coil members is independently controllablerelative to others of the one or more first coil members.

33. A linear actuator according to any of the examples disclosed herein,further comprising one or more second coils members circumscribing thecentral axis, the one or more second coil members arranged to have agreater coil density at the second opposing end of the linear actuatorrelative to a center of the linear actuator, wherein the one or moresecond coil members are configured to produce a second asymmetricalfield distribution having a second peak density toward the secondopposing end of the linear actuator.

34. A linear actuator according to any of the examples disclosed herein,wherein the linear actuator is configured for communication with acontroller, the controller configured to control a ratio of flux densitybetween the first asymmetrical field distribution and the secondasymmetrical field distribution to control one or more of a speed of theplunger moving along the central axis, a position of the plunger on thecentral axis, a direction of movement of the plunger along the centralaxis, or a stroke length of the plunger along the central axis.

35. A linear actuator comprising: a plunger; one or more first coilmembers circumscribing a central axis and comprising a greater number ofoverlapping windings at a first end of the linear actuator relative to acenter of the linear actuator, wherein the one or more first coilmembers are configured to generate a first asymmetrical fielddistribution having a greater flux density at the first end of thelinear actuator; a first variable power source in communication with atleast one of the one or more first coil members; one or more second coilmembers circumscribing the central axis and comprising a greater numberof overlapping windings at a second opposing end of the linear actuatorrelative to the center of the liner actuator, wherein the one or moresecond coil members are configured to generate a second asymmetricalfield distribution having a greater flux density at the second opposingend of the linear actuator; and a second variable power source incommunication with at least one of the one or more first coil members;wherein the one or more first coil members and the one or more secondcoil members are further configured such that one or more of a speed ofthe plunger moving along the central axis, a position of the plunger onthe central axis, a direction of movement of the plunger along thecentral axis, or a stroke length of the plunger along the central axisis controlled via a ratio of flux density between the first asymmetricalfield distribution and the second asymmetrical field distribution.

36. A linear actuator according to any of the examples disclosed herein,wherein the linear actuator is configured for communication with acontroller, the controller in communication with and configured tocontrol power from the first variable power source to the one or morefirst coil members for production of the first asymmetrical fielddensity and control power from the second variable power source to theone or more second coil members for production of the secondasymmetrical field density.

37. A linear actuator according to any of the examples disclosed herein,wherein the plunger comprises two or more plunger segments eachconnected to an adjacent plunger segment by a connection member.

38. A method of operating a linear actuator, the linear actuatorcomprising a plunger, one or more first coil members circumscribing acentral axis and comprising a greater number of overlapping windings ata first end of the linear actuator relative to a center of the linearactuator, and one or more second coil members circumscribing the centralaxis and comprising a greater number of overlapping windings at a secondopposing end of the linear actuator relative to the center of the lineractuator, the method comprising: controlling power from a first variablepower source to the one or more first coil members, the one or morefirst coil members configured to generate a first asymmetrical fielddistribution; and controlling power from a second variable power sourceto the one or more second coil members, the one or more second coilmembers configured to generate a second asymmetrical field distribution;wherein the controlling of power from the first variable power sourceand the controlling of power from the second variable power sourcecomprises generating a specified ratio of flux density between the firstasymmetrical flux density and the second asymmetrical flux density, thespecified ratio of flux density configured to result in one or more of aspecified speed of the plunger moving along the central axis, aspecified position of the plunger on the central axis, a specifieddirection of movement of the plunger along the central axis, or aspecified stroke length of the plunger along the central axis.

39. A computerized controller configured for communication with a linearactuator, the linear actuator comprising a plunger, one or more firstcoil members circumscribing a central axis and comprising a greaternumber of overlapping windings at a first end of the linear actuatorrelative to a center of the linear actuator, and one or more second coilmembers circumscribing the central axis and comprising a greater numberof overlapping windings at a second opposing end of the linear actuatorrelative to the center of the liner actuator, the one or more first coilmembers configured to generate a first asymmetrical flux density, andthe one or more second coil members configured to generate a secondasymmetrical flux density, the computerized controller comprising: acommunication interface configured for communication with each of afirst variable power source for providing power to the one or more firstcoil members and a second variable power source for providing power tothe one or more second coil members; one or more processor apparatus;one or more storage apparatus in communication with the one or moreprocessor apparatus, the one or more storage apparatus comprisingnon-transitory memory storing a plurality of computer-readableinstructions therein, the plurality of computer-readable instructionsconfigured to, when executed by the one or more processor apparatus,cause the computerized controller to: identify a specified ratio of fluxdensity between the first asymmetrical flux density and the secondasymmetrical flux density; control, based at least in part on thespecified ratio of flux density, power flow from the first variablepower source to the one or more first coil members; and control, basedat least in part on the specified ratio of flux density, power flow fromthe second variable power source to the one or more second coil members;wherein, when the control of the power flow from the first variablepower source and the control of the power flow from the second variablepower source comprises causing more power to be applied to the one ormore first coil members relative to the one or more second coil members,the first asymmetrical flux density acts on the plunger to result in atleast one of movement of the plunger toward the first end of the linearactuator or retarding of movement of the plunger toward the secondopposing end of the linear actuator; and wherein, when the control ofthe power flow from the first variable power source and the control ofthe power flow from the second variable power source comprises causingmore power to be applied to the one or more second coil members relativeto the one or more first coil members, the second asymmetrical fluxdensity acts on the plunger to result in at least one of movement of theplunger toward the second opposing end of the linear actuator orretarding of movement of the plunger toward the first end of the linearactuator.

Any feature(s) of any example(s) disclosed herein can be combined withor isolated from any feature(s) of any example(s) disclosed herein,unless otherwise stated. Further, in view of the many possibleembodiments to which the principles of the disclosure may be applied, itshould be recognized that the illustrated embodiments are only examplesand should not be taken as limiting the scope of the disclosed subjectmatter or the claims.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Rather, thescope of the invention is defined by the following claims. We thereforeclaim as our invention all that comes within the scope and spirit ofthese claims.

We claim:
 1. A linear actuator comprising: a plunger; one or more firstcoil members circumscribing a central axis, wherein the one or morefirst coil members are configured to produce a first asymmetrical fielddistribution having a greater flux density at a first end of the linearactuator; and one or more second coil members circumscribing the centralaxis, wherein the one or more second coil members are configured toproduce a second asymmetrical field distribution having a greater fluxdensity at a second opposing end of the linear actuator; wherein the oneor more first coil members and the one or more second coil members arefurther configured such that the each of first asymmetrical flux densityand the second asymmetrical flux density is independently controllableto cause motion of the plunger along the central axis relative to theone or more first coil members and the one or more second coil members.2. The linear actuator of claim 1, wherein the one or more first coilmembers comprises a first coil on a first circuit, the first coilcomprising two or more sections of first windings, each of the two ormore sections of first windings at least partially radially overlappingwith an adjacent section of first windings, the two or more sections offirst windings configured such that there is a greater number ofoverlapping first windings distributed toward the first end of thelinear actuator relative to a center of the linear actuator.
 3. Thelinear actuator of claim 1, wherein the one or more second coil memberscomprises a second coil on a second circuit, the second coil comprisingtwo or more sections of second windings, each of the two or moresections of second windings at least partially radially overlapping withan adjacent section of second windings, the two or more sections ofsecond windings configured such that there is a greater number ofoverlapping second windings distributed toward the second opposing endof the linear actuator relative to a center of the linear actuator. 4.The linear actuator of claim 1, wherein the one or more first coilmembers comprises a plurality of first coil members each on a separatecircuit, wherein each first coil member comprises a portion of firstwindings that radially overlaps with an adjacent first coil member, theplurality of first coil members configured such that there is a greaternumber of overlapping first windings distributed toward the first end ofthe linear actuator relative to a center of the linear actuator.
 5. Thelinear actuator of claim 1, wherein the one or more second coil memberscomprises a plurality of second coil members each on a separate circuit,wherein each second coil member comprises a portion of second windingsthat radially overlaps with an adjacent second coil member, theplurality of second coil members configured such that there is a greaternumber of overlapping second windings distributed toward the secondopposing end of the linear actuator relative to a center of the linearactuator.
 6. The linear actuator of claim 1, wherein the one or morefirst coil members and the one or more second coil members are furtherconfigured such that the each of first asymmetrical flux density and thesecond asymmetrical flux density are independently controllable to stopmotion of the plunger along the central axis relative to the one or morefirst coil members and the one or more second coil members.
 7. Thelinear actuator of claim 1, further comprising a first variable powersource in communication with the one or more first coil members, and asecond variable power source in communication with the one or moresecond coil members.
 8. The linear actuator of claim 1, wherein thelinear actuator is configured for communication with a controller, thecontroller in communication with and configured to control power from afirst variable power source to the one or more first coil members forproduction of the first asymmetrical field density and control powerfrom a second variable power source to the one or more second coilmembers for production of the second asymmetrical field density.
 9. Thelinear actuator of claim 1, wherein the linear actuator is configured tobe controlled such that, when more power is applied to the one or morefirst coil members relative to the one or more second coil members, thefirst asymmetrical flux density acts on the plunger to result in atleast one of movement of the plunger toward the first end of the linearactuator or retarding movement of the plunger toward the second opposingend of the linear actuator.
 10. The linear actuator of claim 1, whereinthe linear actuator is configured to be controlled such that, when morepower is applied to the one or more second coils relative to the one ormore first coils, the second asymmetrical flux density acts on theplunger to result in at least one of movement of the plunger toward thesecond opposing end of the linear actuator or retarding of movement ofthe plunger toward the first end of the linear actuator.
 11. The linearactuator of claim 1, wherein the linear actuator is configured to becontrolled such that, controlling a ratio of flux density of the firstasymmetrical flux density relative to the second asymmetrical fluxdensity results in control of one or more of a speed of the plungermoving along the central axis, a position of the plunger on the centralaxis, a direction of movement of the plunger along the central axis, ora stroke length of the plunger along the central axis.
 12. A linearactuator comprising: one or more first coil members circumscribing acentral axis; and a plunger disposed at least partially within the oneor more first coil members; wherein the one or more first coil membersare configured to produce a first asymmetrical field distribution havinga first peak density toward a first end of the linear actuator; andwherein the first asymmetrical field distribution is configured to havean increased maximum stroke length of the plunger along the central axisrelative to a coil having symmetrical field density and a same length asthe one or more first coil members.
 13. The linear actuator of claim 12,wherein the one or more first coil members comprises a plurality offirst coil members each on a separate circuit, wherein each first coilmember comprises a portion of first windings that radially overlaps withan adjacent first coil member, the plurality of first coil membersconfigured such that there is a greater number of overlapping firstwindings distributed toward the first end of the linear actuator. 14.The linear actuator of claim 13, wherein the linear actuator isconfigured such that a polarity of each of the one or more first coilmembers is independently controllable relative to others of the one ormore first coil members.
 15. The linear actuator of claim 12, furthercomprising one or more second coils members circumscribing the centralaxis, the one or more second coil members arranged to have a greatercoil density at the second opposing end of the linear actuator relativeto a center of the linear actuator, wherein the one or more second coilmembers are configured to produce a second asymmetrical fielddistribution having a second peak density toward the second opposing endof the linear actuator.
 16. The linear actuator of claim 15, wherein thelinear actuator is configured for communication with a controller, thecontroller configured to control a ratio of flux density between thefirst asymmetrical field distribution and the second asymmetrical fielddistribution to control one or more of a speed of the plunger movingalong the central axis, a position of the plunger on the central axis, adirection of movement of the plunger along the central axis, or a strokelength of the plunger along the central axis.
 17. A linear actuatorcomprising: a plunger; one or more first coil members circumscribing acentral axis and comprising a greater number of overlapping windings ata first end of the linear actuator relative to a center of the linearactuator, wherein the one or more first coil members are configured togenerate a first asymmetrical field distribution having a greater fluxdensity at the first end of the linear actuator; a first variable powersource in communication with at least one of the one or more first coilmembers; one or more second coil members circumscribing the central axisand comprising a greater number of overlapping windings at a secondopposing end of the linear actuator relative to the center of the lineractuator, wherein the one or more second coil members are configured togenerate a second asymmetrical field distribution having a greater fluxdensity at the second opposing end of the linear actuator; and a secondvariable power source in communication with at least one of the one ormore first coil members; wherein the one or more first coil members andthe one or more second coil members are further configured such that oneor more of a speed of the plunger moving along the central axis, aposition of the plunger on the central axis, a direction of movement ofthe plunger along the central axis, or a stroke length of the plungeralong the central axis is controlled via a ratio of flux density betweenthe first asymmetrical field distribution and the second asymmetricalfield distribution.
 18. The linear actuator of claim 17, wherein thelinear actuator is configured for communication with a controller, thecontroller in communication with and configured to control power fromthe first variable power source to the one or more first coil membersfor production of the first asymmetrical field density and control powerfrom the second variable power source to the one or more second coilmembers for production of the second asymmetrical field density.
 19. Thelinear actuator of claim 17, wherein the plunger comprises two or moreplunger segments each connected to an adjacent plunger segment by aconnection member.